In recent years, a path to overcoming intractable diseases has been shown by regenerative medicine and regenerative medical therapies that exploit cell tissue engineering/genetic engineering and the like. Mesenchymal tissue-derived adult stem cells, in particular adipose tissue-derived somatic stem cells, which may be collected safely and simply, have been drawing attention as supply sources of cellular materials used in these regenerative medical therapies.
Adipose tissue-derived somatic stem cells may be collected from an adipose tissue by methods that have been already established in the 1980's (Non-patent Reference 1, and Patent References 1 and 2). However, the collection efficiency of such methods is low, with a large number of erythrocytes and vascular endothelial cells contaminating the cell population obtained ultimately. Since the growth efficiency of the contaminating erythrocytes and vascular endothelial cells is higher than that of stem cells, the proportion of stem cells in the cell population decreases when the obtained cell population is cultured. In addition, when the obtained cell population is induced for differentiation, the differentiation efficiency thereof is remarkably low. Consequently, in order to achieve an actual application clinically or in drug screening and the like, development of a method for collecting adipose tissue-derived somatic stem cells with high purity and high yield is needed.    Patent Reference 1: Japanese Translation of PCT Application No. 2002-537849    Patent Reference 2: Japanese Translation of PCT Application No. 2005-502352    Non-patent Reference 1: de la Llera M et al., J. Lipid Res. 1981 February; 22(2): 245-53